Coating composition



Patented June a, 1943 UNIT ii COATING COWOSITION Edward H. McArdle,Linden, N. 3., asslgnor to Standard Oil Development Company, a.corporation of Delaware,

No Drawing. Application October 7, 1939, a Serial No. 298,401

Claims.

This invention relates'to improvements in coating compositions and moreparticularly to coating compositions containing large volumes ofvolatile ingredients and at the same time having normal brushingviscosities.

When coating compositions, either clear varnishes or pigmented vehicles,are being applied, it is very desirable that a uniform layer of thecoating composition be obtained. Properly to level this layer, it isdesirable that the coating composition have a certain brushingviscosity. It is generally the practice to thin the coating compositionby the addition of a hydrocarbon thinner.

Thethinners that were used to a great extent heretofore have beenturpentine and petroleum spirits which evaporate at a rate similar toturpentine.

Such mineral spirits have been composed of small quantities of aromatichydrocarbons together with larger proportions of naphthenes andparaffins. The solvency of naphthene hydrocarbons has been generallyconsidered to be half of that of the corresponding aromatichydrocarbons. Parafilns have been generally considered to'possess asolvency of about half of that of the corresponding naphthenes.

It is an object of this invention to provide a thinner that not onlywill dissolve the coating composition, but also will not reduce thebrushing viscosity to the same degree as would be obtained werethe samevolumes of mineral spirits used.

Themineral spirits that were used heretofore, boiling in themineralspirit range, that is, 300 to 400 Fraud used iorarchitecturalpaints, seldom-have A. P. I. gravities higher than 50. Ac-

cording to thisinvention, branched chain parafrlnic hydrocarbonsproduced by reacting an olefin When a paint vehicle is thinned withconventional low solvency mineral spirits, the resulting viscosity isconsiderably lower than when the same weight of vehicle is thinned withthe same correwithaparaflinichydrocarboncontaining at least spondingweight of alkylates. Therefore, a greater weight of the alkylates can beused when thinning a paint to arrive at the same brushing viscosity. Inthe past, turpentine, having an A. P. I. gravity of 33, had been verywidely used, but as the mineral spirits of from 44 to 50 A. P. I.gravity have largely replaced the turpentine because of the fact that agreater volume of the mineral spirits may be used to obtain the samethin paint viscosity, it is evident that the thinner used according tothis invention, having a still higher A. P. I. "gravity, can be used toadvantage to replace the mineral spirits of from 44 to 50 A. P. I.gravity. The following table illustrates the advantage obtained by usingthe alkylates:

Table 1 Alkylatcs Mineral spirits Specific gravity .752 .783

A. P. I. gravity..degrees. 56. 7 49.8

50% of! volatile point F.. 342 340 VISCOSITIES Oil THINNED COATINGCOMPOSITIONS 505% by weight Bcckasol 50 ccntipoiscs. 40 ccntipoises.

25 gal. ester-gum/China- Il/I SGnrdncr G (Gardner Holdt woodoil-linseedoll;clear Ho dt tubes at tubes at 25 C.) varnish thinned 50/50 25 C.)166.6 141.0 centigoises by weight. 4 ccntig oises at at 100 F. bbel00(Ubbelohde tube). lohde tube).

Same varnish 90 g.: white 74.8 seconds (Ford 6L5 seconds.

lead in oil 50 g. Out at 75 F. #4

White lead in oil 200 g. 13.2seconds (Ford 13.4 seconds.

thinner alone g. Cup at F. #4

Orifice).

Where a white lead-in-oil paint or varnish is thinned with the sameweights of mineral spirits of 50 A. P. I. gravity and alkylates, thedifierence in volume of the two thinners is illustrated as follows:

200 grams of white le'ad-in-oil paste is thinned with 60 g, of mineralspirits of 493 A. P. I. gravity to obtain a volume of 76.5 cc. ofthinned paint. When the same weight of paste is thinned with 60 g. ofthe alkylate having a gravity of 56.7, 79.8 cc. of the thinned paint areobtained having the same brushing viscosity as the one thinned withmineral spirits; that is, 3.3 cc. or 4.3% additional volume of paint areobtainedwhen the alkylate is used. When varnish vehicles "are thinned,that-is, a vehicle weighing 240 g. is thinned with 240 g. of mineralspirits, 310.4 cc. at 77 F. of a varnish are obtained; while where thesame weight of alkylates are used, 325.0 cc.

at 77 F. oi the thinned varnish are obtained. that is, 14.6 cc. or 4.7%more thinned varnish is obtained when the alkylates are used. Since thevehicle thinned with alkylates has a higher viscosity than that thinnedwith mineral spirits, still more alkylates can be incorporated to matchthe brushing viscosity of the mineral spirits varnish.

When a synthetic resin, oi the type employed to increase durability ofcoating compositions, is

aaansos chain paramnic hydrocarbons boiling between 300 and 400 R, an A.P. I. gravity of 53 to 70 and an aniline point between 160 and 195 F.

3. A coating composition comprising a drying oil, and to oi a mixture ofbranched chain paramnic hydrocarbons boiling between 300 and 400 F.,having an A. P. I. gravity of 58 to and an aniline point between and F.

4. A coating composition comprising an ester gum, China-wood oil,linseed oil, and 30 to 50% 01' a mixture of branched chain parafllnichydrocarbons boiling between 300 and 400 F., having an A. P/ I. gravityof 53 to 70- and an aniline point between 160 and 195 F.

5. A coating composition comprising a metal pigment, linseed oil,Chinawood oil and 30 to 50% of a mixture of branched chain paraiiinichydrocarbons boiling between 300 and 400 F., having an A. P. I. gravityof 53 to 70 and an aniline point between 160 and 195 F.

EDWARD H. MCARDLE.

